Heater for grain-driers.



' 0. w. RANDOLPH.

HEATER FOR GRAIN DRIERS. APPLICATION FILED FEB. I5. 19!].

1,262,841 Patented Apr. 16, 1918.

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' HEATER FOR GRAIN DRIERS. APPLICATIION man FEB. 15. 1911.

Patented Apr. 16, 1918.

4 SHEETS-SHEET 2.

O. W. RANDOLPH.

HEATER FOR GRAIN DRIERS.

APPLICATION FILED FEB. 15. 1911.

Patented Apr. 16, 1918.

4 SH EETSSHEET 3- o. w. RANDOLPH.

HEATER FOR GRAIN DRIERS.

APPLICATION FILED FEB. 15. 1917.

1,262,841. Patented Apr. 16, 1918.

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13; a Q \u Q N m E Q a 3X *4 &\. I vi OLIVER W. RANDOLPH, 0F TOLEDO, OHIO.

HEATER FOR GRAIN-DBIERS.

Specification of Letters Patent.

, Patented A r. 1c, 1918.

Application filed February 15, 1917. Serial No. 148,700.

,To all whom it may concern:

Be it known that I, OLIVER W. Rnnnonrn, a citizen of the United States, residing at Toledo, in the .county of Lucas and State of Ohio, have invented new and useful Improvements in Heaters for Grain- Dr1ers, of which the followin is a specification.

My invention re ates to a heater for a grain drier, and has for its ob ect to provlde an economical heater for the purpose that is adapted to utilize substantially all the heat produced by the combustion of fuel in a furnace of the heater, by first heating a'large volume of air to a low temperature while being drawn through the heating tubes of the heater by a forced draft of air drawn through the furnace of the heater and ra1sed to a high temperature, and then minglmg the forced draft of the furnace with the greater volume of air drawn through the heating tubes, whereby the entire volume of air forced through the grain drler 1s raised to and automatically maintained at a desired mean temperature.

A further object is to commingle the gases of combustion with the heated air forced through the grain in the drier, whereby parasitic and other insect life infesting the grain is destroyed, and the grade and quality of the grain is improved. I

T accomplish these objects by the construction and combination of parts as hereinafter described and illustrated in the drawings, in which Figure 1 is a perspective view of a heater constructed in accordance with my inven-,

tion.

Fig. 2 is a reduced top view of the same.

Fig. 3 is a vertical section of Fig. 2 on line wm. I p

Fig. 4 is a vertical section of Fig. 2 on line y-y.

Fig. 5 is a perspective view of a palr of heater units nested together.

Fig. 6 is a side view of a number of heater units assembled together in their alternating order.

. Fig. 7 is a section of Fig. 6 on line az.

Fig. 8 is a perspective view of a b'afiie plate.

Fig. 9 is a screen for the tops of the hoods.

Fig. 10 is a perspective view ofa hot a1r damper, and y Fig. 11 is a diagrammatic v1ew of the heater and its connections with a gram drier.

In the drawings A designates a heater constructed in accordance with my invent1on and comprising the furnace 1, the heater 2, the air mixing chamber 3, the heater hoods 4, and their connections 5 with the mixing chamber, and a magazine fuel feed 6.

The furnace 1 comprises the rectangular metal casing 7 having a fire clay lining 8, a grate 9, the baflie plates 10 above the grate, the draft door 11, and the fuel door 12.

The heater 2 which is mounted on the furnace wall over the front and rear portion of the grate 9, is built up of alternating unit sections a and 6 each comprising a rectangular frame 13 with integral transverse heating tubes 14, havin their bores extending through the sides 0 the frame.

The tops of the frames 13 are provided with rabbets 15 and their bottoms with the tongues 16 complementary to the rabbets 15, and the corners of each frame are provided each with a web 17 perforated to receive a connecting rod 18 by which the units are securely bolted together, and to the furnace casing. I

The tubes 1% of the units 6 are arranged to extend horizontally above the spaces between the tubes of the section a and parallel .therewith, whereby the tubes of one unit operate asdeflectors to direct the gases of combustion against the tubes of the other.

Two equal groups of alternating units a and b are formed and mounted respectively one on the front portion and the other on the rear portion of the furnace casing and between the two groups is fitted the coal feed magazine 6 having a hopper shaped extension Within the furnace chamber, adapted to deliver fuel centrally of the grate.

On the front and rear heater groups are mounted the hoods 4, the tops of which are connected by an arched duct 20 which supports a common flue stack 21.

At one side, the tubes of the two heater groups open into the mixing chamber 3'to which the hools 4 are also connected by the ducts 5. The mixing chamber 3 is also connected by a duct 23 having capacity equal to all the tubes of the heater with a blower fan having connection with the air receiving hood H of a grain drier D and having the capacity to supply air suflicient for the grain capacity of the drier.

The ducts 5 connecting the hoods 4 with the mixing chamber 3 are provided with the dampers 24 which are fixedly mounted 11 by the duct 23 with the 1 duced to maintain on the common arbor 25, one end of which is rovided with abell crank 26.

entrally between the ducts 5, the chamber 3 is also provided with a cold air duct 5 horizontally through which passes the arbor 25 upon which within the duct is fixedly mounted the damper 24 at right angles to the plane of the dampers 24, for a purpose hereinafter described.

The draft door 11 of the furnace is also provided with a bell crank 27, one arm of which is connected with the door, and the other by the chain 29 with one of the arms of the bell crank 26, which is operatively connected with a regulator automatically controlled by a thermostat introduced into the hood H of the grain drier D to which the heater is connected and operating as hereinafter described;

The stack 21 near its connection with the arched duct 20 is provided with a damper 21 adapted to be adjusted to entirely close the stack.

The mixer chamber 3 of the heater A is connected as diagramaticall shown in Fi blower B whic is operatively connected by the driving belt C with a motor (not shown) and by the duct E with the'hood H of the drier D. An air compressor F is operatively connected by a belt f with the pulley e on the axle of the fan of the blower B and by a pipe h with the receiver R from which the pipe 7:; extends to an air gage G connected to a thermostat T installed in the hood H of the drier D, and adapted to control an air escape valve (not shown) of the gage G The pi e k is also connected by a branch pipe is with an air motor L connected to one arm of the bell crank 26 and adapted to operate the bell crank in one direction against the resistance of a spring (not shown) that is adapted to normally and yieldingly hold the bell crank in a position to open the dampers 24 and close the damper 24.

Thus constructed the operation is as follows I The dampers 24 and 24' being in the relative normal position above described before starting a fire in the furnace, the damper 21 in the stack 21 is fully opened and kept in that position until a bed of incandescent coal is on the grate of the furnace, after which the fuel magazine is filled with hard coal or coke, the damper 21 is closed and the blower fan B is started, the suction of which draws air-from the mixing chamber 3 thereby drawing air through the tubes 14 of the heater and also from the furnace chamber through the ducts 5 and the draft doorli with the mixing chamber, whereby a forced draft through the grate is procombustion of the fuel. The tubes 14 are heated by the gases of commixing bustion, passing duct 5 into the mixing v trol the c'ommingling recess-,1

around them on their way to the mixing chamber and in turn heat the air drawn through the tubes 14 into the mixin chamber. I

The thermostat T being adapted by its expansion at a pre-determined degree of heat to commence to close the air valve of the gage Gr and at a predetermined higher degree of heat to fully close the valve, thermostat is made to automatically control the heat in the hood H of the drier D as soon as the temperature of the air in the hood H reaches a degree partly closing the valve of the air gage, at which point the air pressure in the pipe K begins to rise the and to operate the motor L against the tension of its spring, and thereby partly closes the dampers 24 and opens the damper 24', and if the temperature in the hood H rises to the maximum the valve in the gage G is fully closed and the motor L is.

thereby operated to fully close the dampers 24 and fully open the damper 24 whereby heated air and gases from the furnace are almost entirely cut oif "from the mixing chamber and cold air is drawn through the chamber, whereby the temperature is immediately lowered in the hood H and the thermostat opens the valve of the gage G thereby reducing the pressure in the pipe is and permits the spring of the motor L to again open the dampers 24 and close the damper 24', thus automatically regulating the degree of heat in the drier hood H to a temperature between the maximum and minimum predetermined degrees.

By the construction shown and described I obtain an economical supply of air for a drier, heated to a substantially uniform temperature, and by mingling the gases of combustion with the air supply for the drier. in addition to the drying of the grain, I thereby destroy all parasitic insectivora and the like infecting the grain, and thereby improve the quality and grade of the grain.

The specific means shown and described for automatically regulating the dampers of my heater are commonly employed in heating. and ventilating systems, and excepting'in combinations with the blower and the dampers as means to regulate and conof the gases of combustion with the air drawn through the heater tubes and cold air duct, I do not claim them as a part of my invention and do not limit myself thereto, as the same regulation may be accomplished by other thermostatically controlled regulators.

In constructing my dampers 24 and the draft door they are preferably provided with perforations 0, whereby when fully closed they will not entirely out ofi all forced draft through the furnace.

The hoods4 are preferably provided with the screens 30, covering the openings to the ducts extending from the tops of the hoods limit myself to its use with grain driers alone.

Vhat I claim to be new is w 1. A heater for supplying hot air for drying grain and other material, comprising a furnace, a heating chamber for the furnace, an air mixing chamber, air heating tubes extending through the heating chamber and adapted to supply air to the mixing chamber, a duct connecting the heating chamber with the mixing chamber, an air duct adapted to connect the mixing chamber with the air intake of a blower fan, whereby air is, drawn through the heating tubes and both air and gases through the duct of the heating chamber into the mixing chamber, and means to vary the volume of air and gases drawn through the duct from the heating chamber to the mixing chamber, relative to the volume drawn through the heating tubes, and to regulate the degree of heat of the air in the mixing chamber.

2. A' heater for supplying hot air for drying grain and other material, comprising a furnace, a heating chamber for the furnace, an air mixing chamber, air. heating tubes extending through the heating chamber and adapted to supply air to the mixing cham her, a duct connecting the heating chamber with the mixing chamber, an air duct adapted to connect the mixing chamber with the air intake of a blower fan, whereby air is drawn through the heating tubes and both air and gases through the duct of the heating chamber into the mixing chamber, and means to vary the volume of air and gases drawn through the duct from the heating chamber to the mixing chamber, relative to the volume drawn through the heating tubes, and to automatically regulate the degree of heat of the air in the mixing chamber.

3. In a heater for supplying hot air for drying grain and other material, the combination with the air receiving hood of a grain drier, a thermostat installed in the hood, and a blower adapted to deliver air to the hood, of a heater comprising a furnace chamber having a grate, and a draft door adapted to admit air to the furnace chamber below the level of the grate, a heating chamber above the furnace chamber having heater tubes extending through the heater chamber, a mixing chamber adapted to receive air from the heating tubes, a duct connecting the blower with the mixing chamher, and adapting the blower to draw air through the tubes of the heater into the mixing chamber, an. air duct connecting the heating chamber with the mixing chamber, aid air duct connecting the mixing chamber with the atmosphere, a damper controlling each inlet air duct connecting the mixing chamber with the heating chamber and with the atmosphere, the damper controlling the duct connecting the heating chamber with the mixing chamber being normally open, and the damper controlling the air duct connecting the mixing chamber with the atmosphere being normally closed, and means connecting the thermostat of the drier hood with the dampers and adapting the thermostat to automatically and reversely control the dampers.

In testimony whereof I have hereunto set my hand at Toledo, Ohio, this 12th day of February, 1917.

OLIVER W. RANDOLPH.

In presence of- ALBERT T. GOORLEY, RICHARD C. WATSON. I 

